| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.twitter.distributedlog.readahead; |
| |
| import com.twitter.distributedlog.ReadAheadCache; |
| import org.apache.bookkeeper.stats.Gauge; |
| import org.apache.bookkeeper.stats.StatsLogger; |
| |
| import java.util.concurrent.atomic.AtomicLong; |
| |
| /** |
| * ReadAheadTracker is tracking the progress of readahead worker. so we could use it to investigate where |
| * the readahead worker is. |
| */ |
| public class ReadAheadTracker { |
| // ticks is used to differentiate that the worker enter same phase in different time. |
| final AtomicLong ticks = new AtomicLong(0); |
| // which phase that the worker is in. |
| ReadAheadPhase phase; |
| |
| ReadAheadTracker(String streamName, |
| final ReadAheadCache cache, |
| ReadAheadPhase initialPhase, |
| StatsLogger statsLogger) { |
| this.phase = initialPhase; |
| statsLogger.registerGauge("phase", new Gauge<Number>() { |
| @Override |
| public Number getDefaultValue() { |
| return ReadAheadPhase.SCHEDULE_READAHEAD.getCode(); |
| } |
| |
| @Override |
| public Number getSample() { |
| return phase.getCode(); |
| } |
| }); |
| statsLogger.registerGauge("ticks", new Gauge<Number>() { |
| @Override |
| public Number getDefaultValue() { |
| return 0; |
| } |
| |
| @Override |
| public Number getSample() { |
| return ticks.get(); |
| } |
| }); |
| statsLogger.registerGauge("cache_entries", new Gauge<Number>() { |
| @Override |
| public Number getDefaultValue() { |
| return 0; |
| } |
| |
| @Override |
| public Number getSample() { |
| return cache.getNumCachedRecords(); |
| } |
| }); |
| } |
| |
| ReadAheadPhase getPhase() { |
| return this.phase; |
| } |
| |
| public void enterPhase(ReadAheadPhase readAheadPhase) { |
| this.ticks.incrementAndGet(); |
| this.phase = readAheadPhase; |
| } |
| } |